Summer's over, school is back, and students are in the classroom ready to learn again. But did they ever stop? Turns out, people on YouTube spent 15% more time watching educational videos in August 2013 than April. From outrageous science experiments and geographical anecdotes, to lessons on how to become British Royalty or stop an asteroid, people spent over 142 million hours watching educational content on YouTube this summer. That’s nearly 16,200 years of video watched, and more than twice as much as last summer!

And the numbers keep climbing. From 2011 to 2013, views of educational videos during the summer have increased by 99% in the US.

While the views come from a collection of over 46 million videos, we’ve put together a list of the summer’s educational blockbusters and highlighted the top five most-viewed EDU videos of the season. Sure beats summer school, right?